Portable power distribution systems or units are well known in the art and are used to distribute power from a single (or multiple) power source to multiple systems or devices that have usually been set up in a temporary fashion. Typically, portable power distribution systems include at least one input for receiving three-phase electric power from a three-phase generator and a plurality of outputs for distributing the received power as three-phase and/or single-phase electric power. For applications that require power, such as emergency or military applications, these systems are necessary when connection to a stable power grid is not available and when multiple loads need to be connected to a temporary or alternative power source, such as a generator. For example, in military applications it is essential that the command post of a battlefield operation have a continuous supply of power to control weapon systems and operate the communication systems. Accordingly, it is imperative that the integrity of the power supply system remains intact.
Unfortunately however, the stability and reliability of current portable power distribution systems becomes questionable if the distribution system is not balanced. This imbalance is created when the current across all three phases are not equal (or substantially equal) and substantially more current is being drawn on one phase (or more phases) as opposed to the other phases. This imbalance is undesirable because it causes the devices attached to the system to operate less efficiently and can lead to several issues that create adverse situations, such as equipment damage and/or failure, safety hazards and complete power outages (including brownouts). It should be noted that although a perfectly balanced system is hard (if not impossible) to achieve, the more out of balance the system is, the more deleterious the effects are to the components (and performance of the components) connected to the system.
While there are methods to address these issues, many are not only inadequate, many times they are dangerous and impractical to employ. For example, one approach used to properly balance the electrical load across the phases of a generator requires that the attached devices be shutdown and reconnected to different phases. In an emergency medical or military situation, this may require the shutdown or complete disconnect of mission critical devices, such as weapon systems, communication and/or life support devices. Another approach would be to absorb the effects and address the power outages or brownouts that may result from the imbalance using Uninterruptable Power Supplies (UPS). Unfortunately, due to the typical power requirements of mission critical devices the UPS's are insufficient to cover these power outages.